The increased cancer risk (lung, pleural, mesothelioma and colon) associated with direct occupational exposure to asbestos has been well documented. Growing evidence of an increasing prevalence of asbestos associated disease among "bystanders" (non-asbestos trade employees working in close proximity to asbestos workers) is being described. Concern has been extended to members of asbestos worker households (over 70 mesotheliomas reported in the literature). The current study will be the first to systematically examine the mortality experience of a well defined cohort of household members of amosite asbestos workers. During Year I, cohort workers were identified utilizing pre-existing records. Year II has been spent tracing the cohort and establishing vital status. The cohort now contains 2,205 members; all but 511 (23%) have had their vital status determined. Of 1694, whose status has been updated, 1,164 are known alive and 620 deceased. Death certificates are being gathered and 553 have been obtained. Available information has been transcribed onto computer readable cards. Where death certificates indicate that death occurred in a hospital, and especially on those on whom a post-mortem was performed, written permission has been sought to acquire this information. Identification, tracing and updating of the cohort is proceeding as scheduled and is expected to reach 95% of cohort. The information from this study, when combined with the experience of index workers who have been occupationally exposed to the same fiber, from the same source, in the same years and geographical location, will make it possible to establish risk levels for these various asbestos exposures. It should also indicate whether the risk of household asbestos exposure warrants consideration by government, labor and industry and any proposed for surveillance of asbestos exposed individuals.